Piston



G. C. AUSTIN Feb. 21 1928.

PISTON Filed Dec. 14, 1925 Y INVENTOR (fizonc e C. AUSTIN Patented Feb.21, 1928.

NITEDY STATES PATENT OFFICE.

GEORGE G. AUSTIN, OF LOS ANGELES, CALIFORNIA, ASSlEGNOR F ONE-HALF TOSAMUEL QUARTER, OF LOS ANGELES; CALIFORNIA.

PISTON.

Application filed December 14, 1925. Serial No. 75,284.

This invention relates to that type of internal combustion enginepistons shown in my application, Serial No. 598,153, filed October 31,1922,' for United States Letters- Patent for piston, in which thepistonis shown as having ia continuous peripheral slot separating the skirtportion from the head portion; the portions thus separated beingconnected to each other by webs that extend from the head portion to thewrist pin bosses so that the heat of the head portion will betransmitted to the skirt portion only through. said' webs and bosseswhich are subjected to the cooler air nside the 115 open end of thepiston.

It is found in practicev that with sa1d type of piston a distortionoccurs in the periphery of the separated skirt port1on, wh1ch causes twoareas of heavy contact w1th the cylinder separated by areas of lightercontact on each side of the axis of the wrist P111.

An object/of this invention is to prevent such distortion and tomaintain the cylindrical portions of the periphery in true form duringengine operation.

This invention is broadly new, basic and pioneer in that I provide thecyli ndr1ca] portions of the piston on oppos1te sides of the axis-of thewrist pin with internal brldging and such bridging is preferably in theform of thin segmental ribs.symmetr1cally arranged on opposite sides ofthe plane in which the axes of the piston and wrist pin lie.

By this means the expansion of the arcs of the skirt that haveheretofore been subject to said heavy contact with the cylmder, iscontrolled; and such ortions practicall maintain their conformity tothecylindrical walls of the combustion chamber.

Other objects, advantages and features of invention may appear from theaccompanying drawing the subjoined detailed description and the appendedclaims.

The accompanying drawing illustrates the invention.

Figure l isa side elevation of an internal combustion enginepistonconstructed in accordance with this invention with three bridgeson each side of the axial planes of the cylinder and the wrist 'oin.

Fig. 2 is a view looking into the open end of the piston shown in Fig.i.

Fig. 3 is an axial section on line :5 Fig. 1.

Fig. 4 is a cross section on line :12, Figs. 1, 3 and 6.

Fig. 5 is a cross section on line w, Fig. 1. 4 Fig. 6 is an" elevationat right angles to Fig. 1, showing a slot at the lower end of the skirt.

Thepiston is shown provided at its head 1 with the usual peripheralpacking ring grooves 2 the lowermost one of which is extended by aslot 3to separate from the piston head 1 the skirt 4 that is provided withwrist pin bearing bosses 5, which are supported by internally arrangedcolumns 6 extending from the head 1 to the wrist pin bosses 5, whichthey support, thus connecting the head 1 with the skirt 4:. Theprincipal advantage of locating slot 3 .in the lowermost packing ringgroove seat, is that the ring will partially seal the slot and preventan unrestricted flow of lubricating oil through the slot from thecylinder Walls. The oil ring on apiston scrapes the cylinder walls andfunctions to remove the oil therefrom. Should the escape of oil beunrestricted, the upper walls of the cylinder will become dry and aresubject to scoring by the piston proper. This is a ruinous conditionthat has been alleviated in the present invention by the provision ofthe peripheral slot located in the manner stated in con and the wristpin bosses5, lie.

The skirt may or may not be provided'os with the longitudinal andtransverse slots 9 and 10 to give freedom of expansion and contractionto thelower end of the skirt.

In Figs. 1 and 3 said slots are omitted and in Fig. 6' the slots areshown.

I claim.

l. A piston provided with wrist pin bearzoo ings; columns for supportingthe bearings;

a rib integral with the piston head and the base of said columns andsegmental bridging extending transversely of the shirt on op osite sidesof a plane intersecting the co umns and adapted to control the distor- Ition of that portion of the piston skirt that is bridged during theperiod of unequal expansion and contraction of the head and skirt.

2. A piston havin a slot .separatingthe piston head from t e skirt ofthe piston V and having internal columns connecting the skirt with thehead and segmental bridging extending transversely of the skirt on up xv posrte sids of a plane intersectlng the col- 10 umns andodapted tocontrol distortion of that portion of the piston skirt that is bridged.

In testimony whereof, I have hereunto set my hand at Los Angeles,California, this 5th day of December, 1925.

GEORGE e. AUSTIN,

